If the earth were twice the distance from the sun that it is now, the gravitational force exerted on it by the sun would be: a) 1/4 what it is now
b) /2 what it is now
c) twice what it is now
d) 4 times what it is now

a) 1/4 what it is now

Explanation:

As we know that force of gravitation between two planets at some distance "r" from each other is given as

now since we know that if the distance between Earth and Sun is changed

So the force of gravity will be given as

now we know that the distance between sun and earth is changed to twice the initial distance between them

so we have

so new gravitational force between sun and earth is given as